restructure

Match regular expressions into struct fields

This crate is inspired from alexflint/go-restructure

This crate uses a macro regexify! which takes the struct along with its fields and patterns for sub-expressions.

#[macro_use(regexify)]
extern crate restructure;
extern crate regex;

use regex::Regex;
use restructure::{Restruct, RegexStruct};

regexify!(HostName {
  domain, String, r"\w+"
  _dot, String, r"\."
  tld, String, r"\w+"
});

fn main() {

  let host: HostName = Default::default();

  let filled_host = Restruct::fill(&host, "example.com");

  assert_eq!("example", filled_host.domain);
  assert_eq!("com", filled_host.tld);
}

The regular expression that was executed was the concatenation of the struct tags:

(?P<domain>\w+)\.(?P<tld>\w+)

You can see that the fields which start with a _ are not added as captures into the regex. You can use _ with fields which act as seperators or whitespace.

The first submatch was inserted into the domain field and the next into tld field.

The general format of the macro is

regexify!( <struct name> {
	<field_name>, <field_type>, <pattern>
  .
  .
});

regexify! can deal with mixed type structs, making your work easier.

#![feature(cell_extras)]

#[macro_use(regexify)]
extern crate restructure;
extern crate regex;

use std::cell::{RefCell, Ref};
use regex::{Regex, Error};
use restructure::{Restruct, RegexStruct};

regexify!(MovieDetail {
  title, String, r"'[^']+'"
  _1, String, r"\s+\("
  year, i32, r"\d+"
  _2, String, r"\)"
});

fn main() {

  let movie: MovieDetail = Default::default();

  let not_my_favorite_movie = Restruct::fill(&movie, "Not my favorite movie: 'Citizen Kane' (1941).");

  assert_eq!(r"'Citizen Kane'", not_my_favorite_movie.title);
  assert_eq!(1941, not_my_favorite_movie.year);

}

What regexify! does

Apart from declaring the struct specified, it also implements the RegexStruct trait on the defined struct. It also applies the trait std::default::Default on the struct.

TODO

• Nested structs
• Better error handling
• Iterable structs
• JSON conversion (optional)